diff --git a/libraries/Wire/Wire.h b/libraries/Wire/Wire.h
index 528b3b16d..3fe84fabb 100644
--- a/libraries/Wire/Wire.h
+++ b/libraries/Wire/Wire.h
@@ -22,6 +22,7 @@
 #include "Print.h"
 #include "drivers/I2C.h"
 #include "drivers/I2CSlave.h"
+#include "rtos.h"
 
 typedef void (*voidFuncPtrParamInt)(int);